Efficient Generalized Mie Theory Analysis of Nano Silver Dimers for Optical Field Enhancement in the Plasmonic Photoconductive Thz Antenna
Faezeh zarrinkhat
Commsenslab, Universitat Politècnica de Catalunya  BarcelonaTECH
Faezeh Zarrinkhat was born in Iran, in 1990. She received the Bachelor and Master degrees in Telecommunication Engineering, from the Shiraz University of Technology (SUTECH), Shiraz, Iran and khaje Nasir Toosi University of Technology (KNTU), Tehran, Iran in 2012 and 2016, respectively. In 2018 she joined the Signal Theory and Communications Department of Polytechnic University of Catalonia (UPC) as a PhD student, where she is engaged in research in Nanophotonics theory.Her current research interests are application of nanophotonics in THz photoconductive antennas and electromagnetic modeling of living cells.
Abstract
Generalized Mie theory (GMT) is a rigorous analytical method to investigate the optical properties of a cluster of nanospheres, providing useful optical information [1]. We propose a nanodimer configuration, for which a GMT... [ view full abstract ]
Generalized Mie theory (GMT) is a rigorous analytical method to investigate the optical properties of a cluster of nanospheres, providing useful optical information [1]. We propose a nanodimer configuration, for which a GMT matrix equation with size of S=4n(n+2) should be solved, where n indicates the number of modes. To simplify this method for symmetrical nanospheres, we can remove half the mode coefficients due to the symmetry of configuration. If we investigate each optical mode participation to generate the final field coefficients precisely, it will reveal that by eliminating weak mode coefficients the matrix equation size will reduce. It should be noted that decreasing the distance between the nanospheres and increasing the size of them leads to a larger number of significant modes. Also, in the polarization parallel to the symmetry axis the number of the effective modes are larger than for the perpendicular polarization. Figure 1 shows how this approach matches with the GMT.
Photoconductive antennas exhibit significant application such as highefficiency THz generation, THz detection, THz timedomain spectroscopy, and THz imaging. The main problem in this area is optical to THz wave conversion efficiency [2]. The idea is to design a symmetrical nanodimer to resonate at the λ=800nm, which is a commercial laser wavelength. By applying a cluster of silver nanodimers between the electrodes of a PC antenna, plasmons will be stimulated at such configuration and intensify the local electrical field of the laser pump beam. This approach enhances the ratio of the generated THz photocurrent power to the optical power in the PC material, which is the opticaltoelectrical efficiency. The accuracy and efficiency of the GMT allows us to design improved configurations, optimizing the size of the nanospheres, interparticles distance, material, the angle of the incident plane wave, and the permittivity of surrounding medium. Figure 2 depicts the electrical field distribution for a silver nanodimer configuration that resonates at λ=800nm. The physical properties presented in table 1.
 D.W Mackowski, Proc. R. Soc. A 443, 599–614 (1991)
 C.W. Berry, et al. Nat. Commun. 4, 1622 (2013)
 P. B. Johnson, et al. Physical Review 6 (12), 43704379 (1972)
Authors

Faezeh zarrinkhat
(Commsenslab, Universitat Politècnica de Catalunya  BarcelonaTECH)

Jordi Romeu
(Commsenslab, Universitat Politècnica de Catalunya  BarcelonaTECH)

Juan Rius
(Commsenslab, Universitat Politècnica de Catalunya  BarcelonaTECH)

Lluis Jofre
(Commsenslab, Universitat Politècnica de Catalunya  BarcelonaTECH)
Topic Area
Photonic & plasmonic nanomaterials
Session
OS2bA » Photonic & plasmonic nanomaterials (16:50  Tuesday, 2nd October, AUDITORIUM)
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